Installation of wood millwork with pre-applied adhesive

ABSTRACT

Wood millwork (e.g., wood trim molding for use around door openings) is installed by means of pre-applied adhesive (e.g., pressure sensitive adhesive strips) which is bonded to the generally planar underside of the moulding and activated at the time of use (e.g., activated by removing protective films or with solvents). Preferably, the adhesive is bonded to the millwork at the time of manufacture. Such millwork can be installed on site with the use of substantially fewer nails than now used commercially.

United States Patent 1 Stark 1 Aug. 7, 1973 INSTALLATION OF WOOD MILLWORK WITH PRE-APPLIED ADHESIVE Inventor: Joseph L. Stark, Minneapolis, Minn.

Chippewa Lumber Industries, Inc., Glidden, Wis.

Filed: May 28, 1971 Appl. No.: 148,013

Assignee:

US. Cl 144/315, 161/167, 156/322 Int. Cl B2741 1/00 Field of Search 161/167; 156/291,

References Cited UNITED STATES PATENTS Deskey 144/309 A Daubert et al 161/167 X 2,984,598 5/1961 Gobalet 156/322 X Primary Examiner-Andrew R. Juhasz Assistant Examiner-W. D. Bray Attorney-Merchant & Gould [57] ABSTRACT Wood millwork (e.g., wood trim molding for use around door openings) is installed by means of preapplied adhesive (e.g., pressure sensitive adhesive strips) which is bonded to the generally planar underside of the moulding and activated at the time of use (e.g., activated by removing protective films or with solvents). Preferably, the adhesive is bonded to the millwork at the time of manufacture. Such millwork can be installed on site with the use of substantially fewer nails than now used commercially.

4 Claims, 6 Drawing Figures INSTALLATION OF WOOD MILLWORK WITH PIKE-APPLIED ADHESIVE BACKGROUND OF THE INVENTION Wood millwork such as moulding and trim (hereinaf ter collectively referred to as wood millwork) are elongated strips of wood which have at least one generally planar wall engaging or contact surface and at least one decorative exposed surface. The exposed surface(s) of wood millwork is shaped (i.e., milled) to provide decorative and functional features.

Wood moulding or casing of the type used to frame door openings is a typical example of wood millwork. Wood door casing is used to cover the line of contact between the vertical wall surface (e.g., dry wall or plaster) and the door jamb that lines the door opening.

Wood door casing is frequently made of hardwood (e.g., oak). It is cut at the construction site and then fastened in place with finishing nails. Because of the hardness of the wood, it is ordinarily desirable and necessary to drill holes in the door casing to serve as guides for the finishing nails. The nails are then driven into the wood door casing through the drilled holes. Nailing is terminated when the nail head is slightly above the decorative exposed surface of the wood door casing. The nail is then driven slightly below the outer surface of the wood using a nail set.'Next, the small hole or void above the head of the nail is filled with putty, plastic or wax which is colored to match the finish on the wood. Ordinarily, nails are spaced along the nose or thin edge of the wood door casing or moulding and they are driven through the nose of the door easing into the edge of the wood door jamb. Another row of nails is placed along the heel or thick edge of the wood door moulding. These nails are driven through the heel into the wall (e.g., dry wall).

Because wood millwork, particularly door and window moulding, is installed in the foregoing manner, the cost of labor in completing such installations is a source of concern to those engaged in the building trades. Moreover, nailing wood door moulding in place re quires that the door jamb be made of solid wood. Plywood and particle board (which are less expensive than solid hardwood) cannot be used for various reasons. For example, plywood tends to de-laminate when nailed into from its exposed edges.

As a consequence of the foregoing, those engaged in the building trades are constantly looking for new methods of installing, wood millwork (such as door moulding or casing), which methods will result in lower on site labor costs. They are also searching for ways to utilize non-solid wood door jambs (e.g., plywood door jambs) to thereby reduce costs.

Adhesives, although commonly used with plastic trim which cannot be nailed, are not ordinarily used with wood millwork. Moreover, if adhesives are used on site for the application of wood trim, extreme care must be taken to avoid smearing adhesive on surfaces to be finished (e.g., by staining).

SUMMARY OF THE INVENTION According to the present invention, an adhesive (e.g., double-faced or double coated contact or pressure sensitive adhesive strips) is pre'applied to the generally planar reverse or non-exposed side of wood millwork, preferably at the time the millwork is created, and the adhesive is rendered inactive or non-adherent (e.g., by covering the exposed adhesive surface with a protective plastic film). The wood millwork is then cut to dimension on site, the adhesive is activated (e.g., by solvent activation or by removing protective strips), and the millwork is installed by pressing in place (e.g., around a door opening). By the proper use of preapplied, on site activated adhesives, the requirement for nailing the wooden millwork in place can be reduced or eliminated entirely (i.e., nail-less construc tion). Moreover, the problems associated with the onsite application of adhesives can be avoided.

The present invention results in significant labor savings for on site construction because the repetitive steps of drilling, nailing, countersinking, and puttying can be reduced in number (e.g., reduced to three nails per meter of millwork) or eliminated entirely. Occasionally, the use of a few nails in installing wood door moulding may be desirable. However, these nails can be placed in the heel of the wood door moulding, thereby avoiding the necessity for nailing into the edge of the wood door jamb. Because of these features, it is possible to construct the wood door jamb for non-solid (i.e., synthetic) wooden materials such as plywood and particle board which may be vinyl covered, etc.

THE DRAWINGS FIG. Iis a plan view of a vertical wall and door showing wood door moulding in place.

FIG. 2 is a fragmentary sectional view of the door assembly of FIG. I as taken along the lines 2-2 in the direction of the arrows.

FIG. 3 is a perspective view of a prior art wood door moulding.

FIG. 4 is a perspective view of a wood door moulding having strips of double-faced adhesive bonded to the generally planar underside thereof.

FIG. 5 is a perspective view of wood door casing having a hot melt adhesive bonded to the generally planar underside thereof.

FIG. 6 is a cross-sectional view of an alternative embodiment of adhesive-backed wooden door moulding.

DETAILED DESCRIPTION Although the present invention is broadly applicable to wooden millwork, the description hereinafter given is made with particular reference to wood door moulding or casing for purposes of illustration, only.

FIG. 1 shows a door I hinged on a door jamb consisting of wooden frame elements 3, 4, and 5. The door is equipped with hinges 6 and 7. The wall 8 can be of any construction (e.g., dry wall, plaster, panelling, or the like). Wood door moulding 9, l0, and I1 is attached to the wall 8 and the door jamb elements 3, 4, and 5 by means of nails (in conventional construction) or by means of a pre-applied adhesive (as described herein).

The details of constructionof the door assembly of FIG. I are further illustrated in FIG. 2 which is a frag mentary sectional view of the door assembly of FIG. 1 as taken along the line 2-2 in the direction of the arrows. As shown in FIG. 2, the door assembly includes:

door 1, door jamb 5, wall 8, stud l2, shim l3, and door stop 14. As seen in FIG. 2, wood. door moulding ll overlaps the seam between wall 8'and door jamb element 5. In conventional construction, wood door moulding I1 is held in place by driving nails through the nose a of door moulding 11 into door jamb element 5 and by driving nails through the heel b of door moulding I1 into wall 8.

A perspective view of conventional wood door moulding is shown in FIG. 3. This moulding, 11, has a nose a and a heel b. The bottom or non-exposed side of door moulding 11 is slightly relieved. Historically, the purpose of this slight relief on the reverse or bottom side of the wood moulding was to accommodate differences in thickness and evenness where the wall 8 of FIG. I abuts against door jamb elements 3, 4, and 5. The need for this relieved area has diminished greatly with the advent of dry wall construction and modern construction techniques. However, the consuming public tends to view wood door moulding which does not have a relieved reverse or underside to be of inferior quality.

Although wood door moulding of conventional design (see FIG. 3) can be used satisfactorily in the practice of the present invention, it is convenient to use wood door moulding which is flat on the reverse or underside for purposes of the present invention. In FIG. 4, a wood door moulding 15 is shown which has a flat or planar underside to which has been attached several intermittent and alternate strips 16, 17, and 18 of double-faced adhesive. These strips are spaced along the transverse margins of the flat underside of the moulding 15. The side of these adhesive strips facing the underside of the wooden moulding is in direct contact with and bonded to the wood. The exposed or bottom faces of adhesive strips l6, l7, and 18 are rendered inactive by covering those surfaces with easily removable protective film or paper strips which can be removed on site at the time it is desired to install wood door moulding according to the method of the present invention.

Although the adhesive can be pre-applied over the entire planar bottom or under surface of wood door moulding or can be pre-applied in one or more separate, continuous strips, it is advantageous to use intermittent strips or spots of adhesive for several reasons. First, if too much adhesive is used, it becomes difficult to adjust the position of the moulding if it is put into place incorrectly on site. It also becomes extremely difficult to later remove the door moulding from a wall if such becomes necessary for purposes of repairs or the like. Additionally, modern adhesives are available which give sufficient bonding power to enable wood millwork such as door mouldings to be held in place with as little as about 5 square centimeters of adhesive per lineal foot of door moulding (the area refers to contact area on the wall side of the moulding). Economically, it is desirable to use the minimum amount of adhesive that will provide a satisfactory bond under the conditions of use.

FIG. 5 illustrates the pre-application ofa hot melt adhesive to a door moulding 19 in a continuous ribbon 20 and in spots 21. A pre-applied hot melt adhesive (e.g., HM-030-R, a product of H. B. Fuller Company, St. Paul, Minnesota) becomes inactive after application as a result of cooling and hardening. Such adhesives can be activated on site by the use of heat or by contact (e.g., wiping) with an appropriate solvent (e.g., trichloroethylene). With other hot melt adhesives, other solvents (e.g., water or liquid hydrocarbons) can be used for activation.

The adhesive is desirably applied or attached to the wood door moulding as the moulding is created (i.e., as

it is discharged in an elongated strip from a milling machine). The reason for doing this is that the adhesive bonds more firmly to the wooden moulding if the adhesive is applied to a warm surface. When the wood is ejected from the milling machine, it is warmer than room temperature. The bond between the adhesive and the millwork improves with time. This results in an adhesive strength differential when comparing the strength of the bond between an adhesive strip and the wooden moulding with the strength of the bond between the adhesive strip and the door jamb or wall immediately after installation. This adhesive differential causes the adhesive strip to remain attached to the wooden moulding if it becomes necessary to remove the wooden moulding from the wall shortly after it is put in place (e.g., to correct alignment). However, after a wooden door moulding has been in-stalled in place for an extended period of time, the strength of the bond between the adhesive strip and the wall or door jamb increases and approaches the strength of the bond between the adhesive strip and the wooden door moulding.

FIG. 6 illustrates another alternative embodiment in which a wood door moulding 22 is provided with two longitudinally extending channels or grooves 23 and 24 which accommodate approximately one-half the thickness of intermittently spaced adhesive 25 and 26 (e.g., double coated adhesive strips which are covered with protective backings 27 and 28). The purpose of partially embedding the adhesive 25 and 26 in the underside of the door moulding 22 is to protect the adhesive from damage in handling caused by shear forces.

A variety of adhesives can be used in the practice of the present invention although all do notserve with equal effectiveness. Double-backed adhesive tapes of the contact or pressure sensitive types are well suited to the practice of the present invention. Pressure sensitive adhesive strips such as those coated with butadienestyrene copolymers are particularly effective (e.g., SCOTCH brand foam adhesive tape No. Y-933l manufactured by the 3M Company, St. Paul, Minnesota). Hot melt adhesives are especially preferred because they are generally easier to apply to wood millwork, they penetrate the surface of the wood, they inactivate themselves on cooling, and they can be activated on site with heat or solvents (e.g., activated by merely wiping the pre-applied hot melt adhesive with a rag soaked in a non-flammable solvent).

What is claimed is:

l. The process which comprises the steps of:

a. milling elongated wood strips to create wood millwork having at least one decorative surface and at least one contact surface, said millwork being warmer than room temperature when first created; and

b. applying at least one double faced adhesive strip to said contact surface while said millwork is warmer than room temperature.

2. The process of claim 1 wherein adhesive strips are spaced intermittently along transverse margins of said contact surface.

3. The process which comprises the steps of:

a. milling elongated wood strips to create wood millwork having at least one decorative surface and at least one contact surface, said millwork being warmer than room temperature when first created; and

6 b. applying adhesive to said contact surface while stalled.

mmwork warmer than room temperature 4. The process of claim 3 in which said adhesive is a said adhesive being capable of 1. being inactivated for storage; and 2. re-activated when said millwork is to be in- 5 hot melt adhesive. 

2. The process of claim 1 wherein adhesive strips are spaced intermittently along transverse margins of said contact surface.
 2. re-activated when said millwork is to be installed.
 3. The process which comprises the steps of: a. milling elongated wood strips to create wood millwork having at least one decorative surface and at least one contact surface, said millwork being warmer than room temperature when first created; and b. applying adhesive to said contact surface while said millwork is warmer than room temperature, said adhesive being capable of
 4. The process of claim 3 in which said adhesive is a hot melt adhesive. 